<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package	Zend_Search_Lucene
 * @subpackage Search
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license	http://framework.zend.com/license/new-bsd	 New BSD License
 */


/** Zend_Search_Lucene_Search_Query */
require_once 'Zend/Search/Lucene/Search/Query.php';

/** Zend_Search_Lucene_Search_Query_MultiTerm */
require_once 'Zend/Search/Lucene/Search/Query/MultiTerm.php';


/**
 * @category   Zend
 * @package	Zend_Search_Lucene
 * @subpackage Search
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license	http://framework.zend.com/license/new-bsd	 New BSD License
 */
class Zend_Search_Lucene_Search_Query_Range extends Zend_Search_Lucene_Search_Query
{
	/**
	 * Lower term.
	 *
	 * @var Zend_Search_Lucene_Index_Term
	 */
	private $_lowerTerm;

	/**
	 * Upper term.
	 *
	 * @var Zend_Search_Lucene_Index_Term
	 */
	private $_upperTerm;


	/**
	 * Search field
	 *
	 * @var string
	 */
	private $_field;

	/**
	 * Inclusive
	 *
	 * @var boolean
	 */
	private $_inclusive;

	/**
	 * Matched terms.
	 *
	 * Matched terms list.
	 * It's filled during the search (rewrite operation) and may be used for search result
	 * post-processing
	 *
	 * Array of Zend_Search_Lucene_Index_Term objects
	 *
	 * @var array
	 */
	private $_matches;


	/**
	 * Zend_Search_Lucene_Search_Query_Range constructor.
	 *
	 * @param Zend_Search_Lucene_Index_Term|null $lowerTerm
	 * @param Zend_Search_Lucene_Index_Term|null $upperTerm
	 * @param boolean $inclusive
	 * @throws Zend_Search_Lucene_Exception
	 */
	public function __construct($lowerTerm, $upperTerm, $inclusive)
	{
		if ($lowerTerm === null  &&  $upperTerm === null) {
			throw new Zend_Search_Lucene_Exception('At least one term must be non-null');
		}
		if ($lowerTerm !== null  &&  $upperTerm !== null  &&  $lowerTerm->field != $upperTerm->field) {
			throw new Zend_Search_Lucene_Exception('Both terms must be for the same field');
		}

		$this->_field	 = ($lowerTerm !== null)? $lowerTerm->field : $upperTerm->field;
		$this->_lowerTerm = $lowerTerm;
		$this->_upperTerm = $upperTerm;
		$this->_inclusive = $inclusive;
	}

	/**
	 * Get query field name
	 *
	 * @return string|null
	 */
	public function getField()
	{
		return $this->_field;
	}

	/**
	 * Get lower term
	 *
	 * @return Zend_Search_Lucene_Index_Term|null
	 */
	public function getLowerTerm()
	{
		return $this->_lowerTerm;
	}

	/**
	 * Get upper term
	 *
	 * @return Zend_Search_Lucene_Index_Term|null
	 */
	public function getUpperTerm()
	{
		return $this->_upperTerm;
	}

	/**
	 * Get upper term
	 *
	 * @return boolean
	 */
	public function isInclusive()
	{
		return $this->_inclusive;
	}

	/**
	 * Re-write query into primitive queries in the context of specified index
	 *
	 * @param Zend_Search_Lucene_Interface $index
	 * @return Zend_Search_Lucene_Search_Query
	 */
	public function rewrite(Zend_Search_Lucene_Interface $index)
	{
		$this->_matches = array();

		if ($this->_field === null) {
			// Search through all fields
			$fields = $index->getFieldNames(true /* indexed fields list */);
		} else {
			$fields = array($this->_field);
		}

		foreach ($fields as $field) {
			$index->resetTermsStream();

			if ($this->_lowerTerm !== null) {
				$lowerTerm = new Zend_Search_Lucene_Index_Term($this->_lowerTerm->text, $field);

				$index->skipTo($lowerTerm);

				if (!$this->_inclusive  &&
					$index->currentTerm() == $lowerTerm) {
					// Skip lower term
					$index->nextTerm();
				}
			} else {
				$index->skipTo(new Zend_Search_Lucene_Index_Term('', $field));
			}


			if ($this->_upperTerm !== null) {
				// Walk up to the upper term
				$upperTerm = new Zend_Search_Lucene_Index_Term($this->_upperTerm->text, $field);

				while ($index->currentTerm() !== null		  &&
					   $index->currentTerm()->field == $field  &&
					   $index->currentTerm()->text  <  $upperTerm->text) {
					$this->_matches[] = $index->currentTerm();
					$index->nextTerm();
				}

				if ($this->_inclusive  &&  $index->currentTerm() == $upperTerm) {
					// Include upper term into result
					$this->_matches[] = $upperTerm;
				}
			} else {
				// Walk up to the end of field data
				while ($index->currentTerm() !== null  &&  $index->currentTerm()->field == $field) {
					$this->_matches[] = $index->currentTerm();
					$index->nextTerm();
				}
			}

			$index->closeTermsStream();
		}

		if (count($this->_matches) == 0) {
			return new Zend_Search_Lucene_Search_Query_Empty();
		} else if (count($this->_matches) == 1) {
			return new Zend_Search_Lucene_Search_Query_Term(reset($this->_matches));
		} else {
			$rewrittenQuery = new Zend_Search_Lucene_Search_Query_MultiTerm();

			foreach ($this->_matches as $matchedTerm) {
				$rewrittenQuery->addTerm($matchedTerm);
			}

			return $rewrittenQuery;
		}
	}

	/**
	 * Optimize query in the context of specified index
	 *
	 * @param Zend_Search_Lucene_Interface $index
	 * @return Zend_Search_Lucene_Search_Query
	 */
	public function optimize(Zend_Search_Lucene_Interface $index)
	{
		throw new Zend_Search_Lucene_Exception('Range query should not be directly used for search. Use $query->rewrite($index)');
	}

	/**
	 * Return query terms
	 *
	 * @return array
	 * @throws Zend_Search_Lucene_Exception
	 */
	public function getQueryTerms()
	{
		if ($this->_matches === null) {
			throw new Zend_Search_Lucene_Exception('Search has to be performed first to get matched terms');
		}

		return $this->_matches;
	}

	/**
	 * Constructs an appropriate Weight implementation for this query.
	 *
	 * @param Zend_Search_Lucene_Interface $reader
	 * @return Zend_Search_Lucene_Search_Weight
	 * @throws Zend_Search_Lucene_Exception
	 */
	public function createWeight(Zend_Search_Lucene_Interface $reader)
	{
		throw new Zend_Search_Lucene_Exception('Range query should not be directly used for search. Use $query->rewrite($index)');
	}


	/**
	 * Execute query in context of index reader
	 * It also initializes necessary internal structures
	 *
	 * @param Zend_Search_Lucene_Interface $reader
	 * @throws Zend_Search_Lucene_Exception
	 */
	public function execute(Zend_Search_Lucene_Interface $reader)
	{
		throw new Zend_Search_Lucene_Exception('Range query should not be directly used for search. Use $query->rewrite($index)');
	}

	/**
	 * Get document ids likely matching the query
	 *
	 * It's an array with document ids as keys (performance considerations)
	 *
	 * @return array
	 * @throws Zend_Search_Lucene_Exception
	 */
	public function matchedDocs()
	{
		throw new Zend_Search_Lucene_Exception('Range query should not be directly used for search. Use $query->rewrite($index)');
	}

	/**
	 * Score specified document
	 *
	 * @param integer $docId
	 * @param Zend_Search_Lucene_Interface $reader
	 * @return float
	 * @throws Zend_Search_Lucene_Exception
	 */
	public function score($docId, Zend_Search_Lucene_Interface $reader)
	{
		throw new Zend_Search_Lucene_Exception('Range query should not be directly used for search. Use $query->rewrite($index)');
	}

	/**
	 * Highlight query terms
	 *
	 * @param integer &$colorIndex
	 * @param Zend_Search_Lucene_Document_Html $doc
	 */
	public function highlightMatchesDOM(Zend_Search_Lucene_Document_Html $doc, &$colorIndex)
	{
		$words = array();

		foreach ($this->_matches as $term) {
			$words[] = $term->text;
		}

		$doc->highlight($words, $this->_getHighlightColor($colorIndex));
	}

	/**
	 * Print a query
	 *
	 * @return string
	 */
	public function __toString()
	{
		// It's used only for query visualisation, so we don't care about characters escaping
		return (($this->_field === null)? '' : $this->_field . ':')
			 . (($this->_inclusive)? '[' : '{')
			 . (($this->_lowerTerm !== null)?  $this->_lowerTerm->text : 'null')
			 . ' TO '
			 . (($this->_upperTerm !== null)?  $this->_upperTerm->text : 'null')
			 . (($this->_inclusive)? ']' : '}');
	}
}

